With widespread use of three-dimensional (3D) televisions (TVs), 3D video content based on storage media and 3D video content transmission based on digital broadcasting have rapidly come into widespread use. In addition, 3D audio content based on the 3D effect has been widely applied not only to video content but also to audio content.
With the increasing development of such digital technology, users have continuously requested more precise audio/video (A/V) experiences. In order to maximize A/V experiences in response to user demand, an advanced sound system to which the stereo sound and surround sound technology capable of being applied to a general home theater system (HTS) are applied has emerged.
Since most TVs or HTSs have two speakers, the stereo sound system is generally used to provide sound experience to users. However, since a high-end HTS has two or more speakers, the surround sound system has been widely used to provide users with more gentle and precise sound experiences.
Recently, there has been intensively discussed 3D audio technology for reproducing the direction and distance within the 3D sound space to generate the 3D sound effect, thus providing 3D sound. In the 3D audio technology, an acoustic sweet spot in which sound reproduction is controlled, i.e., the position or range within which users can listen to the best sound, may be some parts of the 3D space and user-audible sound.
In addition, 3D video technology and 3D audio technology can be respectively applied to content, and demand for 3D content to which 3D video technology and 3D audio technology are simultaneously applied is rapidly increasing. That is, although demand for 3D content to which the 3D video effect and the 3D audio effect are independently applied using legacy 3D video technology and legacy 3D audio technology is increasing, demand for 3D content acquired by synchronization between the 3D video effect and the 3D audio effect is more rapidly increasing.